import java.util.LinkedList;
import java.util.Queue;

public class BankServiceSystem {
    Queue<Integer> queue=new LinkedList<>();
    int num=0;

    public  void getNum()
    {
        queue.offer(num++);
        System.out.println("顾客取号，号码为："+ queue.size()+"前面还有"+(queue.size()-1)+"人");

    }
    public void callNum()
    {
        if(queue.peek()!=null)
        {
            System.out.println("窗口叫号，编号为"+ queue.peek()+"的顾客到窗口办业务");
        }
        else
            System.out.println("窗口叫号，当前没有排队顾客");
    }
}
